Mold for dental model

ABSTRACT

A mold for forming a dental model base includes a bottom portion having a rear wall and a side wall at a periphery thereof which extends upwards to define a cavity. The walls have upper edges which define an opening to the cavity. The mold further includes a shaping element for forming a connection element of a pivot mechanism at the dental model base which rotationally mates with a corresponding connection element of the articulator.

RELATED APPLICATIONS

[0001] This application is a divisional of application Ser. No.09/584,675, filed May 31, 2000, which is a continuation of applicationSer. No. 09/236,155 filed Jan. 22, 1999, now U.S. Pat. No. 6,089,863which is a continuation-in-part of application Ser. No. 08/916,533 filedAug. 21, 1997, now U.S. Pat. No. 5,957,688 which claims priority to U.S.Provisional Application No. 60/024,297 filed Aug. 22, 1996. The entireteachings of the above-referenced applications are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

[0002] In the fabrication of dental prosthetics, such as false teeth orcaps, a negative impression is made of the teeth of a dental patientusing a thermoplastic material. The negative impression is then filledwith a hardenable material to form a die. The die is affixed to a baseformed of similar hardenable material to form a dental model. A dentalmodel articulator is used to correlate upper and lower dental models inthe forming and adjustment of the dental prosthesis.

[0003] The appeal of using a one-use or dispensable articulator is oneprimarily of time. A reusable articulator needs to be mounted to themodels of the teeth with dental plaster, which requires considerabletime in the processes of mixing, placing, curing, clean-up and then thesubsequent removal of the hardened plaster from the models andarticulator after completion of the prosthesis so as to allow re-use ofthe articulator. Dispensable articulators can save the time involvedwith these steps and have the added advantages of allowing the completedwork to be returned to the dentist still articulated to allowverification of the mounting and to increase the presentation value ofthe case. Typically, a one-use articulator is secured to the dentalmodels using an adhesive, thereby eliminating the use of plaster. Toallow this, the articulator must provide a mechanism to adapt glueablemembers to angular differences of surfaces on the models. Such amechanism is not needed as part of a reusable articulator because itsmembers are allowed a large range of angular and positional differenceswithin the masses of plaster that are used to affix the articulator tothe models.

[0004] Multiaxial adaptation is a primary consideration in designing asuccessful one-use articulator. One approach is to use an adaptive pivotmechanism that allows multiaxial adjustment between a hinge and one orboth models. U.S. Pat. Nos. 4,382,787, 4,865,544 and 5,425,636 disclosearticulator designs that adapt to the models using ball and socketjoints which are then immobilized with adhesive or friction. Thisapproach forces a tradeoff, in that the joints must be kept small inorder to provide the required amount of angular adjustment which in turnreduces the surface area of the joints, thereby limiting reliableimmobilization.

[0005] Another approach of adaptation is to use an extensible member ormembers and allow adjustment of these in conjunction with a hinge jointaxis to provide accommodation of these glueable surfaces to thedifferences of the orthogonal axes that share each of the top and bottomsurfaces of the models. Accommodation of the remaining axes ofdifference orthogonal to these surfaces is accommodated simply byallowing a range of angular adjustment about these axes when gluing tothese surfaces. Examples of this type are found in U.S. Pat. Nos.5,046,949 and 5,221,203. A drawback to this approach is that thearticulators are typically more complex in design and are larger in sizeand material requirements, as they have to provide structure both aboveand below the models which makes this type more expensive to producethan the previous examples which can be affixed to the posteriorsurfaces of the models. A primary shortcoming found in all of these andall prior art one-use articulators observed and researched is theinability to properly allow for lateral and protrusive translatorymotions between the articulated models.

[0006] An early dental related patent, U.S. Pat. No. 1743, dated Aug.28, 1840, describes a dental articulator that has provision for “actionsimilar to that of the living subject” which is accomplished by using asliding point of axis in the articulating joints to allow for these“live” translatory motions. Since then, many types and forms of dentalarticulators have been patented and manufactured ranging from extremelycomplex and expensive devices, to the more recent trend of usingdisposable or dispensable one-use articulators. U.S. Pat. No. 3,727,311describes a very simple design connecting the models with a singleresilient rod. This resilience allows translational motions, but thisdesign lacks true hinging action. The previously mentioned U.S. Pat. No.5,046,949 has a conventional hinge, but has no inherent provision forallowing translatory motions.

[0007] An articulator in wide use today is disclosed in U.S. Pat. No.4,449,930, which is a continuation-in-part to the previously mentioned4,382,787, and U.S. Pat. No. 4,548,581 which discloses the samearticulator. The articulators disclosed in the '930 and '581 patentsattempt to allow functional translatory motions by having the technicianflex bracket members connecting the models to the hinge. However, thisflexing requires considerable force which inhibits the feel of thenatural motion paths. Also, the forces of this flexing exacerbate theaforementioned weakness of the adaptive ball and socket pivot mechanism.Because this one adaptive element allows motions on any axis beforeimmobilization and has to withstand the flexing forces of both hingearms after immobilization, the adhesive required to immobilize thesemotions is very critical, since it must lock all of the axial forces andalso fix the socket half of the pivot mechanism to the model. Thisrequires that the adhesive used in the joints be of high quality andthat its application be technique sensitive. If misapplied or if theglue is old or too high in viscosity, then failure of the adhesivewithin the ball and socket joint or between the model and socket becomeslikely.

[0008] In U.S. Pat. No. 4,449,930 the socket half of the adaptive jointis incorporated into the model base which simplifies the design.However, molding the socket into the base is not practical since itwould eliminate the ability to laterally align the sockets to set thehinge axis sagittally perpendicular. To make this design approachpractical, the socket needs to be a separate piece to allow it a rangeof lateral placement on the model which requires another glue joint tofix the socket to the model base. There is described in a related patentU.S. Pat. No. 4,481,162 a mold which forms a slot in the rear of thedental model for receiving a corresponding key on the socket half of thejoint.

[0009] A further improvement on this same design by the same inventor isdisclosed in U.S. Pat. No. 4,734,033. This improvement specificallyaddresses translatory motion by making the hinge brackets more flexiblebut even with this enhancement the articulator fails to allow truesliding motions between the models, since there is still strictly asingle axis rotational motion allowed by the hinge joints.

[0010] Translational motions are an extremely important function to beprovided by an articulator in the task of fabricating dentalprosthetics. The technician must be able to freely check all of thepossible lateral and protrusive motions that the patient uses inmastication. If the technician is impeded in doing this, then invariablythe prosthesis will need adjustment by the dentist during placement inthe mouth (or perhaps even remanufacture) which results in considerableaggravation for the patient and dentist. None of the prior art one-usearticulators have been found to be both simple of design (to allowinexpensive manufacture and thus dispensability) and permissive of truetranslatory motions.

SUMMARY OF THE INVENTION

[0011] This invention relates to dental model articulators as used inthe fabrication of dental prosthetics to provide and allow respectivemovements between an upper and lower set of dental models representingthe natural dentition of the patient. More particularly, this inventionrelates to one-use articulators and to a flexible mold for forming thebase of a dental model to have a connection element of a pivot mechanismfor mating with such articulators.

[0012] An object of the present invention is to provide an articulatorthat does not inhibit the replication of true masticatory motionsbetween articulated dental models. Another object of the presentinvention is to provide an articulator that is very simple and henceinexpensive to produce.

[0013] Yet another object of the present invention is to provide anarticulator that is not technique sensitive in its implementation.

[0014] Yet still another object of the present invention is to providean articulator that requires a minimal amount of material to produce butstill achieves a strong broad connection to the models.

[0015] Yet a further object of the present invention is to provide anarticulator that does not require locking more than one axis of anadaptive pivot mechanism.

[0016] A still further object of the present invention is to provide adesign that provides fewer and stronger adhesive connections to themodels.

[0017] Another object of the present invention is to allow articulationof models with a large variation of dimensional differences.

[0018] Another object of the invention is to provide a mold tofacilitate the forming of a dental model base to include a connectionelement of a pivot mechanism for mating with an articulator.

[0019] The present invention is directed to a dispensable articulatorfor the production of dental prosthetics that provides an accuraterelative positioning of a corresponding pair of dental model casts. Inthe discussion of prior art one-use articulators it was pointed out thatmultiaxial adaptation is a key feature in the design of this type ofarticulator. The essence of the present invention is to combine thismultiaxial motion into hinge joints and to provide pivot mechanismsconnecting the articulator to the models that require only one axis ofadjustment and subsequent fixation. Eliminating the need to lock or fusemultiaxial motions in adaptive pivot mechanisms is a primary advantageof the present invention. Aside from the obvious and inherent strengthof these adaptive joints needing only a single axis of adjustment, theirlineal nature also allows the adjacent halves of these mechanisms foreach model to be laterally combined, incorporated into and made to spanthe width of the model thus allowing a wide range of lateral positionalplacement for the mating elements without requiring the additional glueinterfaces that would be manifest if these were separate components.

[0020] Accordingly, a preferred embodiment of a dental model articulatorfor connecting upper and lower dental models includes an arm havingfirst and second arm segments and an intermediate hinge joint forjoining the first and second arm segments to provide hinging motionabout a hinge axis. The first and second segments each terminates at adistal end in an arm connection element that is pivotally engageablewith a model connector of one of the upper and lower dental models. Eacharm connection element is pivotable about a single pivot axis. The hingejoint comprises a node and a pair of cymbals having opposingundersurfaces which include detents for receiving the node therebetween.The node is attached to one of the first and second arm segments at aproximal end of the respective arm segment. The pair of cymbals isattached to the other of the first and second arm segments at a proximalend.

[0021] According to another aspect of the invention, a flexible moldforms a dental model base that includes cylindrical connection elementsof a pivot mechanism for mating with corresponding connection elementsof an articulator. A portion of the pivot mechanism is integrated intothe dental model to simplify the design of the articulator. The pivotmechanism is lineal in nature thereby allowing adjacent halves of thearticulator to be laterally combined and made to span the width of themodel. This combination provides for a wide range of lateral positionalplacement for the mating connection elements of the articulator withoutrequiring additional glue surfaces that could be needed for separatecomponents.

[0022] Accordingly, a mold for forming a dental model base includes abottom portion having a rear wall and a side wall at a periphery thereofwhich extends upwards to define a cavity. The walls have upper edgeswhich define an opening to the cavity. The mold further includes ashaping element for forming a connection element of a pivot mechanism atthe dental model base which rotationally mates with a correspondingconnection element of the articulator.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

[0024] FIGS. 1 to 3 show perspective posterior, side and rear views,respectively, of a first embodiment of an articulator of the presentinvention having two articulator arms mounted to full arch dentalmodels.

[0025]FIG. 4 is a rear view of one arm of the articulator of FIG. 1.

[0026]FIG. 5 is a rear view of either the upper or lower half of botharms of the articulator of FIG. 1 interconnected.

[0027]FIG. 6 is a partial cross-sectional view of one hinge joint of thearticulator.

[0028]FIG. 7 is a perspective view of a clip for mounting to a dentalmodel base in accordance with the present invention.

[0029]FIG. 8 is a rear view of an alternate embodiment of an articulatormanufactured as a single piece.

[0030]FIG. 9 is a perspective view of the hinge joints of thearticulator of FIG. 8.

[0031]FIG. 10 is an illustration of a flexible rubber mold used to forma dental model base so as to include mating pivot mechanism elements foreach arm of the articulator which are combined to form a singlehalf-round channel traversing the posterior of the model.

[0032]FIG. 11 is a dental model base such as would be formed by the moldof FIG. 10.

[0033]FIG. 12 is a cross-sectional view of the flexible rubber mold ofFIG. 10.

[0034]FIG. 13 is a perspective view of an alternate embodiment of aflexible mold used to form a dental model base.

[0035]FIG. 13A is a perspective view of an alternate embodiment of aflexible mold having vertically separated recesses.

[0036]FIG. 14 is a cross-sectional view of the flexible mold of FIG. 13.

[0037]FIG. 15 is a perspective view of a dental model such as would beformed by the mold of FIG. 13 shown with a teeth model embedded therein.

[0038]FIG. 16 is a perspective side view of the dental model of FIG. 15shown engaged with an arm segment of the articulator of FIG. 1.

[0039]FIG. 17 is a perspective view of another alternate embodiment of aflexible mold used to form a dental model base.

DETAILED DESCRIPTION OF THE INVENTION

[0040] Referring to FIGS. 1-4, an embodiment of an articulator 100redintigrating a pair of full arch dental models 10 and 11 is thereshown. The articulator 100 comprises a pair of arms 33, 34 that areidentical in structure. It should be noted that the followingdescription generally employs a pair of reference characters to refer toa particular element or feature of the respective arms. The arms 33, 34each include an arm segment 33 b, 34 b and a pair of parallel,bifurcated arm segments 33 a, 34 a. The parallel arm segments 33 a, 34 aterminate at a distal end in cylindrical rod-like elements 35, 38 and ata proximal end in a pair of coaxial cymbals 60, 61. The arm segment 33b, 34 b terminates at a distal end in cylindrical rod-like element 36,37 and at a proximal end in node 40, 41. The node is retained betweenthe pair of cymbals 60, 61 supported by the bifurcated arm segments 33a, 34 a to form a hinge joint 20, 21.

[0041]FIG. 4 illustrates arm 33 which is identical to arm 34. Apreferred assembly of articulator 100 is formed by connecting the arms33, 34 to each other in a complementary fashion to provide a singleassembly for ease of handling. Specifically, the complementaryconnection is formed by snap-fitting cylindrical stem 35 a intocylindrical rod-like element 36 and stem 38 a into element 37 to formthe articulator shown in FIGS. 1-3. Referring to FIG. 5, the portion ofarm 33 that includes parallel arm segments 33 a is shown connected tothe portion of arm 34 that includes arm segment 34 b.

[0042] A model connector defining a single axis pivot mechanism isincorporated into the base of each model 10, 11 in the form oftransverse half-cylinders or channels 12 and 13 which traverse theposterior of the models (FIGS. 1 and 3). The channels can be either cutinto the existing models or formed when the models are cast to provideconnection at a range of angles about the radial axis of the transversechannels for mating the cylindrical rod-like elements 35, 36, 37, 38which form the complement to these pivot mechanisms. While the channels12, 13 are shown located on the posterior of the models, it is alsopossible to locate the channels at the top or bottom of the respectivemodels. In alternate embodiments, the channels can instead be formed atthe distal ends of the arm segments and the cylindrical elements can beincorporated in the models to provide the single axis connexus.

[0043] The cylindrical elements 35, 36, 37, 38 have sufficienttransverse axial width such that any adjustment motion of thecylindrical elements within the channels is limited to radial motionabout the channel axis and transverse motion along this axis. With thedental models placed at a closed and centric occlusal (i.e., closedbite) relationship as shown in FIG. 2, the arm segments of therespective arms intersect at an angle α of between approximately 40 to170 degrees, the angle being dependent upon the vertical distancebetween the models 10 and 11.

[0044] It should be noted that while it is preferable to interconnectthe arms 33, 34 to form a single assembly for ease of operation asdescribed above, it is also possible to keep the arms 33, 34 unconnectedfor individual attachment to the dental models. This alternateconfiguration allows the arms 33, 34 to be separated laterally toprovide a closer approximation to the positioning of thetemporomandibular joints of the patient. The attachments of suchunconnected arms can be made to the same channels 12, 13 or to separatechannels on the models that need not be parallel nor coaxial.

[0045] The multiaxial motion provided by the articulator of the presentinvention will now be described. Referring again to FIG. 5, node 40, 41includes two opposed outwardly facing convex portions 40 a, 41 a.Referring to FIG. 6, a partial cross-section of one joint 20 of thearticulator is shown. The cymbals 60, 61 are concave and toroidal inshape. When the node 40, 41 is engaged with the cymbals 60, 61, theconvex portions 40 a, 41 a of each node 40, 41 are held in depressionsor detents 60 a, 61 a at the center of each cymbal by resilience of thematerial in the bifurcated arm segment 33 a, 34 a.

[0046] The primary rotational motion of the node between the parallelarm segments is radial to an axis B that is shared coaxially by thecymbals. Because node 40, 41 and its connected arm segment 33 b, 34 bhas no fixed axis when captured between the cymbals 60, 61, hingingmotion between the arm segment 33 b, 34 b and parallel arm segments 33a, 34 a is allowed an amount of orthogonal deviation from the axis B,that is, motion is provided about a set of orthogonal axes. Thismultiaxial motion of the hinge joint 20, 21 allows the cylindricalconnection elements 35, 36, 37, 38 at the extremities of the arms 33, 34to align with the nonparallelism that is likely to exist between thechannels 12, 13 of models 10, 11.

[0047] Multiaxial motion is only required and exhibited during alignmentof the articulator 100 to the models. Once the two arms of thearticulator 100 are affixed to the models, the only axial motion allowedby the articulator between the models is about a single axis A definedtogether by the two hinge joints 20, 21 (FIG. 1). This common transversehinge axis A lies intejacent and posterior to the dental models 10, 11and is approximately perpendicular to a sagittal plane of the models.

[0048] Each bifurcated arm segment 33 a, 34 a includes a resilient pawlor latch 50, 51 that is used to increase or decrease pressure (i.e.,compression) on the node 40, 41 between the cymbals 60, 61. The pawlincludes a hooked portion 50 a, 51 a for engagement through opening 33c, 34 c in the bifurcated arm segment 33 a, 34 a. When the pawl isengaged, it increases the resilient pressure on the node between thecymbals to an amount that effectively limits or restrains any motionbetween the arm segments 33 a, 33 b and 34 a, 34 b to rotational motionabout the common axis A. Releasing the pawl lessens the resilience to anamount such that protrusive and retrusive motions are permitted betweenthe articulated models 10, 11 by allowing the cymbals to move apart,thereby permitting the convexities of the node to slide across thesurfaces 60 b, 61 b of the cymbals. This free sliding motion is thenlimited in excursion by ridges 70, 71 at the periphery of the cymbals.Note that while the multiaxial motion about the hinge joints 20, 21 isused for alignment of the articulator, the free sliding motion is usedfor simulation of lateral and protrusive translatory motions once thearticulator has been aligned and mounted to the models.

[0049] In an alternate embodiment, the channels can be in the form ofclips that are affixed externally to the models. FIG. 7 shows a clip 90that includes a channel 92 formed therein for receiving a cylindricalelement of the arm segments. A transverse projection or shelf 94extending along the length of the clip 90 is adapted for mounting theclip to a dental model base of the type having an indexing slot.Alternatively, a clip without the shelf 94 can be mounted directly to aflat wall of a dental model base.

[0050]FIGS. 8 and 9 illustrate an alternate embodiment of an articulator200 that provides simple hinging motion between the models and can bemanufactured as one piece. In this embodiment, model connection elements235, 236, 237, 238 are joined with webs 72 and 73 that allow separatetorsional movements of the joined elements. Hinge elements 260, 261,which are best illustrated in FIG. 9, are relieved at areas 81 and 82 topromote the primary hinging action and are relieved at areas 83 and 84to allow orthogonal alignment of the primary hinge axis.

[0051] To use the articulator embodiments of the present invention,channels 12, 13 are cut or molded into the base of the dental models 10,11. These channels 12, 13 are made with sufficient diameter and radialdepth to receive the corresponding arm connection elements 35, 36, 37,38 of the arms 33, 34. In alternate embodiments, the channels can bemade to provide a slight interference frictional fit with the armconnection elements. In the case of the first embodiment, the matingsegments 33 a, 33 b and 34 a, 34 b of each arm of articulator 100(FIG. 1) are assembled so as to form two separate hinge jointed arms.The two arms 33, 34 are then joined together at their adjacent armconnection elements 35, 36, 37, 38 so that each pair of connectionelements is held adjacent and coaxial. This allows the articulator 100to be handled as one flexible unit as would be the case when handlingthe second embodiment 200 (FIG. 8) of the invention. The models 10, 11are placed at the proper closed and centric occlusal relationship andheld either by hand or other means known to a person skilled in the artof dental laboratory procedures. A temporary placement and alignment ofthe arm connection elements 35, 36, 37, 38 of the articulator 100 ismade into the respective channels 12, 13 on the models by adjusting theangular relationships of the arms within the hinge joints 20, 21 definedby each node/cymbal pair 40, 60 and 41, 61 respectively. The articulator100 is fixed by introducing an adhesive within the connexus formedbetween the arm connection elements 35, 36, 37, 38 and the modelconnection elements 12, 13 and allowing it to cure. Once fixed, thearticulator hinge joints 20, 21 allow simulation of occlusal andmasticatory motions between the models.

[0052] The articulator embodiments described herein are capable of beingmanufactured inexpensively. The articulators can be made of plastic suchas nylon, glass-filled nylon, polycarbonate or glass-filledpolycarbonate.

[0053] Referring now to FIG. 10, a flexible rubber mold 300 suitable forforming a dental model base 400 (FIG. 11) for use with the articulatorembodiments of the present invention is shown. A cross-sectional view ofthe mold 300 is shown in FIG. 12. The mold 300 is of flexible rubberconstruction and includes a cavity 310 formed by a back wall 312 and acurved side wall 314 projecting upward to edge 320 from a horizontalbottom portion 316. The back wall 312 includes a convex portion 318 thatextends along the length of the back wall and into the cavity 310 forforming a half-round channel 410 traversing the posterior 412 of thedental model base 400. Preferably, the convex portion 318 extendshorizontally along the full length of the back wall 312.

[0054] To use the mold 300 to form the dental model base 400, which isshown in FIG. 11, a hardenable material such as pourable dental stone orplaster is poured into the mold. After the material hardens, the dentalmodel base 400 is removed from the mold 300 by pushing upward againstthe bottom portion 316 to raise the anterior 414 of the dental modelbase upward about the convex portion 318 until the base completelydisengages from the mold. The half-round channel 410 functions as apivot mechanism element for receiving connection elements 35, 36, 37, 38of articulator 100 or connection elements 235, 236, 237, 238 ofarticulator 200 as described hereinabove.

[0055] Referring now to FIGS. 13 and 14, an alternate embodiment of aflexible rubber mold 500 suitable for forming a dental model base 600(FIG. 15) for use with the articulator embodiments of the presentinvention is shown. The mold 500 is of flexible rubber construction andincludes a cavity 523 defined or formed by a back wall 522 and a curvedside wall 521 projecting or extending upward from a horizontal bottom orfloor portion 516. The upper edges 520, 524 of walls 522, 521respectively define an opening to the mold.

[0056] The back wall 522 includes recesses 510, 511 which extendhorizontally along a portion of the back wall. Recesses 510, 511 arespaced apart and are defined in part by excurvate cylindrical elements512, 513, respectively, and by incurvate surfaces 530, 532,respectively, as shown in the cross-sectional view of FIG. 14. Theexcurvate cylindrical elements 512, 513 are longitudinal sections of acylinder. The excurvatures of the excurvate cylindrical elements arecoaxial with an axis lying between the recesses and oriented in atransverse relationship to the rear wall.

[0057] An alternate embodiment of the mold shown in FIG. 13A includesvertical portions 525 a, 525 b of the back wall 522 which separaterecesses 510 a, 510 b and 511 a, 511 b. The vertical portions 525 a, 525b form additional surfaces in the back wall of the base 600 describedbelow.

[0058] The mold 500 can be used to form the dental model base 600 shownin FIG. 15 using pourable dental stone or plaster as described above.The dental model base 600 includes stanchions 541, 542 which protrudefrom a back wall 545 and correspond to recesses 510, 511, respectively.The stanchions 541, 542 include incurvate elements 543, 544 whichcorrespond to and are formed by the excurvate elements 512, 513,respectively, of mold 500 (FIG. 14).

[0059] The incurvate elements 543, 544 function as a pivot mechanismelement for receiving connection elements 35, 36, 37, 38 of articulator100 or connection elements 235, 236, 237, 238 of articulator 200 asdescribed hereinabove. This can be seen in FIG. 16, wherein anarticulator arm 33 is shown connected to the stanchions 541, 542 ofdental model base 600. In particular, connection element 35 of arm 33engages with, or mates to, the incurvate elements 543, 544 to form apivot mechanism at the dental model base with motion about a singlepivot axis as shown.

[0060] Another alternate embodiment of a flexible mold 700 is shown inFIG. 17. The mold 700 includes a cavity 710 defined or formed by a backwall 712 and a curved side wall 714 projecting or extending upward froma horizontal bottom or floor portion 716. The upper edges 722, 724 ofwalls 712, 714 respectively define an opening to the mold. In thisembodiment, the back wall 712 is essentially flat. The mold includesexcurvate elements 761, 762 located at the sides of the mold cavity 710and adjacent the back wall 712.

[0061] While this invention has been particularly shown and describedwith references to preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the spirit and scope of theinvention as defined by the appended claims. Those skilled in the artwill recognize or be able to ascertain using no more than routineexperimentation, many equivalents to the specific embodiments of theinvention described specifically herein. Such equivalents are intendedto be encompassed in the scope of the claims.

What is claimed is:
 1. A mold for forming therein a dental model baseuseable with a dental articulator, the mold comprising: a bottom portionhaving a rear wall and a side wall at a periphery thereof extendingupwards to define a cavity, the walls having upper edges defining anopening to the cavity; and a shaping element for forming at a portion ofthe dental model base a complement to the shaping element, thecomplement defining a connection element of a pivot mechanism whichrotationally mates with a corresponding connection element of thearticulator.
 2. The mold of claim 1 wherein the rear wall includes afirst recess and wherein the shaping element comprises a first excurvatecylindrical element in the first recess for forming at the dental modelbase a stanchion having an incurvature corresponding to the excurvatureof the cylindrical element.
 3. The mold of claim 2 wherein the rear wallfurther includes a second recess spaced apart from the first recess, thesecond recess including therein a second shaping element comprising asecond excurvate cylindrical element, the excurvature of the first andsecond excurvate cylindrical elements being coaxial with an axis lyingbetween the recesses and oriented in a transverse relationship to therear wall.
 4. The mold of claim 1 wherein the shaping element comprisesa convex portion extending into the cavity for forming a concave channelat the dental model base to which channel the articulator can beattached to form a pivot mechanism.
 5. The mold of claim 4 wherein theshaping element comprises a pair of convex portions formed at opposingends of the side wall.
 6. The mold of claim 1 wherein the shapingelement comprises an excurvate cylindrical element for forming at thedental model base an incurvature corresponding to the excurvature of thecylindrical element.
 7. The mold of claim 6 wherein the excurvature ison the rear wall and wherein a cylinder axis is oriented in a transverserelationship to the rear wall.